‘When Boris Johnson ran for office in 2008, he opposed the closure of 40 ticket offices by his predecessor Ken Livingstone.’

Over the coming days strike action by London Underground staff will be characterised in certain quarters as the action of out-of-control union “barons” intent on “holding the country to ransom”.

Last week the rich were threatening to elope if Labour introduced a 5p increase in the top rate of income tax; this week London Underground staff will walk out over a plan to close every single tube ticket office and cut up to 1,000 jobs.

Yet only one of the above will be on the receiving end of vitriol in the press. I’m sure you can hazard a guess as to which one.

Particularly lamentable is the extent to which London mayor Boris Johnson is escaping the scrutiny visited upon those who will be walking out.

In his £250,000-a-year weekly column for the Daily Telegraph, the mayor wrote that, while he did not begrudge Bob Crow his holiday, the Rail Maritime and Transport (RMT) boss was not entitled to “disrupt the lives of millions of people who are not on holiday but who want to work”.

“It is absolutely outrageous that London, the motor of the UK economy – now contributing 25% of GDP – should be held to ransom by this tiny minority,” he wrote.

The assumption is that it is the union boss, rather than the mayor of London, who is rocking the boat unnecessarily by leading his members on a walkout.

What short memories the mayor and his supporters have.

Whether or not ticket office closures on the London Underground are inevitable, almost no criticism is being levelled at Johnson (I won’t call him Boris, because he’s not my friend) for pledges made by him while running for mayor in 2008 and then again in 2012.

In his manifesto he also promised to ensure that “there is always a manned ticket office in every station”. He repeated this promise again in 2010. And yet today the closure of ticket offices is being billed as something which tube workers should have been expecting all along – despite the fact that the mayor had been saying the opposite for a number of years.

Three quarters (77%) of RMT members who voted in the ballot backed strike action, whereas Johnson won the 2012 mayoral election with 55% of the vote – and many who voted for the mayor did so under the impression that he would not close London Underground ticket offices.

If nothing else, the mayor’s giant U-turn is certainly more newsworthy than pictures of Bob Crow sunning himself in Rio de Janeiro.